Recently, there have been an increased number of vehicles equipped with a data recording apparatus, which is sometimes referred to as an event data recorder (EDR). When a predetermined condition, for example, for activation of an occupant protection device (e.g., airbag) is satisfied in an accident of a vehicle such as a crash, the data recording apparatus records vehicle information (e.g., acceleration) for a predetermined period before and after the condition is satisfied. The recorded information is used for an investigation of the accident.
U.S. 2007/0032930A corresponding to JP-A-2007-45221 discloses such a data recording apparatus. In a vehicle equipped with an occupant protection device, it is necessary to detect acceleration information of the vehicle to activate the occupant protection device. In order to provide redundancy for activation of the occupant protection device, i.e., in order to accurately activate the occupant protection device, the acceleration information is detected by using two sensors, a main sensor and a safing sensor. A controller for controlling activation of the occupant protection device determines whether the condition for activation of the occupant protection device is satisfied based on both the acceleration information detected by the main sensor and the acceleration information detected by the safing sensor.
In the conventional data recording apparatus, the information recorded for the period before and after the condition is satisfied is derived from only the acceleration information detected by the main sensor. Since the recorded information contains acceleration information detected after the accident, it is difficult to determine whether the recorded information is accurate.